Electronics, Lighting, & Gadgets - Alternate power source for bike light

I hope this question is OK. I tried searching in the Total Geekiness thread but did not quite find what I was looking for. I just got a shark light from MEC and it puts out decent light but requires 4 AAA batteries. Is it reasonable to just use the bulb section and somehow wire it to use a different power source? Any links, tips or advice would be great.

1w LED Shark Light:
http://www.mec.ca/Products/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524442621577&FOLDER%3C%3Efolder_id=2534374302692895&bmUID=1197860589287

If you are looking for a longer lasting power supply, a couple lengths of wire and a connector soldered to the final battery contacts along with a 4 cell AA, C or D battery holder from Radio Shack would be fairly straightforward to do.:)
Unless you had something else in mind?:(
Mike

What do you want from the new power supply? If you just want to be able to recharge, you can use rechargeable AAAs in it with no modifications. More burntime, do what Mike suggested. No batteries at all, maybe you can wire it to a dynohub (http://www.bikeforums.net/showthread.php?t=252941), although I'm not sure what the advantage would be compared to ready-made dynamo LED lights.

--J

You can make an adapter from a fiberglass tent pole salvaged from a defunct tent. Here is a photo of a Mag light 3-watt LED flashlight with an adapter I made.
http://i143.photobucket.com/albums/r154/n4zou/batteryadaptor.jpg
I had to drill a small hole in the battery cap for the wire to pass through. I used a battery holder from mouser.com to hold 2 "D" batteries as this flashlight used 2 "AA" batteries. I used it all summer on my road bike this year and the batteries never gave out. The fiberglass is much smaller than "AA" batteries so I used some white medical tape wrapped around the tubing so it's held centered in the battery compartment in the flashlight. you can see the tape in the photo. you should be able to do the same with your light.

Basically I'm just looking to be able to use a battery size that is more convenient for me. I have two AA rechargers and would prefer not to have to go out and buy a AAA recharger and batteries on top of what I already have. The LEDs are pretty good concerning power consumption so burn time os not really an issue. Does battery size affect the number of batteries required? To replace four AAA do I use the same amount of AA or C cell batteries?

n4zou, forgive me I'm new at this. What kind of wire did you use? From what I've seen the tubing is just to hold the wires in place?

To replace four AAA do I use the same amount of AA or C cell batteries?

Yes. As long as you use the same chemistry (eg NiCad, NiMH, alkaline, etc) each single battery will yield the same voltage but bigger batteries have more capacity (will last longer) than smaller ones. There are slight voltage differences between rechargeable and alkaline batteries but for LED lights, it shouldn't matter.

n4zou, forgive me I'm new at this. What kind of wire did you use? From what I've seen the tubing is just to hold the wires in place?
just some scrap wire from an old computer accessory. It had one red wire and one black wire so it was perfect for this use. The tubing has connections made from wire terminals. Each end inmates the ends of 2 "AA" batteries that would have been in the flashlight. The positive wire runs through the tubbing and contacts the connection where the positive post of the battery would be. On the back end where the negative post of the battery would contact the spring in the battery cap is another contact and a washer (again made from a wire terminal) so the spring will not hang up when your turning the battery cap. This allows using two "D" size battery's externally mounted from the flashlight for a much longer burn time.

Yes. As long as you use the same chemistry (eg NiCad, NiMH, alkaline, etc) each single battery will yield the same voltage but bigger batteries have more capacity (will last longer) than smaller ones. There are slight voltage differences between rechargeable and alkaline batteries but for LED lights, it shouldn't matter.

Got it! This makes sense.


just some scrap wire from an old computer accessory. It had one red wire and one black wire so it was perfect for this use. The tubing has connections made from wire terminals. Each end inmates the ends of 2 "AA" batteries that would have been in the flashlight. The positive wire runs through the tubbing and contacts the connection where the positive post of the battery would be. On the back end where the negative post of the battery would contact the spring in the battery cap is another contact and a washer (again made from a wire terminal) so the spring will not hang up when your turning the battery cap. This allows using two "D" size battery's externally mounted from the flashlight for a much longer burn time.

Cool. This might well be the way for me to go.